The present invention relates to an optical type distance measuring device using image sensors, and more specifically, a vehicle-to-vehicle distance measuring device for continuously measuring a distance from a measuring vehicle to a forerunning vehicle.
The conventional optical type distance measuring devices using image sensors are disclosed in Japanese Patent Publication Nos. Sho. 63-38085 and Sho. 63-46363. Any of those devices, as shown in FIG. 12, contains right and left optical systems including lenses 1 and 2, respectively, spaced from each other by as much as a base length L. Image sensors 3 and 4 are disposed at the positions of the focal length f of the lenses 1 and 2, respectively. A signal processor 30 electrically superimposed the image signals from the image sensors 3 and on each other while successively shifting the image signals from one sensor with respect to the image signals from the other sensor, and calculates, by the following equation, a distance R from the measuring vehicle to an object 31 by using a quantity (d) of a displacement of the images of which image signals are best coincident with each other, on the basis of the principle of the trigonometric measurement.